Apparatus for obtaining fibers from plant leaves



J. M CRAE Nov. 1, 1955 APPARATUS FOR OBTAINING FIBERS FROM PLANT LEAVES4 Sheets-Sheet 1 Filed Dec.

uvnulinmunnnfillllimui I INVENTOR ATTORNEY Nov. 1, 1955 J. MCCRAEAPPARATUS FOR OBTAINING FIBERS FROM PLANT LEAVES Filed Dec. 14, 1951 4Sheets-Sheet 2 INVENTOR -4 Ma C1645 ATTORNEY J. M CRAE Nov. 1, 1955APPARATUS FOR OBTAINING FIBERS FROM PLANT LEAVES 4 Sheets-Sheet 3 FiledDec. 14, 1951 00.. noon.

INVENTOR J )z/M (5945 ATTORNEY J. M CRAE I Nov. 1, 1955 APPARATUS FOROBTAINING FIBERS FROM PLANT LEAVES 4 Sheets-Sheet 4 Filed Dec. 14, 1951IN VENTOR BY MW ATTORNEY United States Patent Office 2,722,039 PatentedNov. 1, 1955 APPARATUS FDR OBTAINING FIBERS FROM PLANT LEAVES JamesMcCrae, Anzures, Mexico Application December 14, 1951, Serial No.261,647

4 Claims. (Cl. 19-28) This invention relates to a method of andapparatus for deriving fibers from plant leaves.

It is the object of the present invention to provide a process fordecorticating the leaves of fiber-bearing plants and directly obtainingthe fibers entirely and exclusively in the form of tow, withoutintermediate manufacturing steps.

The invention is applied particularly to the decortication of the leavesof plants to derive the leaf fibers entirely in the form of tow, incontradistinction to the decortication of the stems or stalks of plantswhich results in the obtention of bast fibers.

It is another object of the present invention to decorticate vegetableleaves to effect a separation between the fibrous content and the pulpyportions thereof with maximum yield of fibers and with minimum damagethereto as a result of the decorticating and separating operations.

The invention is particularly applicable to effect such separation offibers from fiber-bearing plant leaves which heretofore has presentedmany difficulties, the invention being applicable particularly tomembers of the Liliacae family such as various varieties of Sansevieria;members of the Bromeliacae family such as Annas Sativa, commonly knownas pineapple; Aechmea Magdalenae, commonly known as silk grass orColumbian pita; members of the Agave family such as Sisalana, Fourcroya,Gigantea, and others; members of the palm family such as Izote; andmembers of the banana family such as Musa textilis.

This invention is designed to decorticate plant leaves and to producethe contained fibers directly and in their entirety in the form of tow.This fibrous form is in contradistinction to line fibers in which thefibers are of substantially the same length as the vegetable leaf fromwhich the same is derived and in which the fibers are in substantialparallelism. Different textile manufacturing operations require thefibers employed therein to be in these two different forms, namely, inthe tow or line form. For example, in the field of textile technologyinvolving the manufacture of burlap or hessian, the fabric used forbagging and commonly made from jute fibers, it is necessary that thefiber be in the form of tow. Therefore, one of the first steps in jutemanufacture is to convert the fiber into a form of tow. In accordancewith the present invention the fiber from the plant leaves is producedin the form of tow directly, without the necessity of any converting oradditional manufacturing steps.

The method of decortication as commonly practiced with plant leavesinvolves a scraping and beating action to remove matter extraneous tothe contained fibers. This action generally is applied in a directionextending longitudinally to the axis of the leaves and transmitsstresses in the same direction to the contained fibers. A well knownresult of stressing fibers longitudinally by this form of decorticationis to break, tear, and otherwise damage a substantial proportion ofthem. It is also well known that leaves of certain plants which containfibers of commercial usefulness remain largely unused on account ofthese longitudinal stresses causing breakage and loss of fibers beyondeconomical limits.

It is therefore the object of the instant invention to avoid stressingof the fibers longitudinally so that the fibers which are obtained arenot broken, torn or otherwise damaged and so that substantially the fulland entire fiber content of the plant leaves is recovered without lossor waste or fibers.

The instant invention proceeds upon the principle of exerting apredetermined crushing action on the plant leaves by means of a seriesof smooth rolls, coupled with a preliminary separation of the fibrousand extraneous components of the plant leaves, which separation issubsequently completed by suitable washing and agitating operations. Inorder to aprpeciate more fully the functions performed by the crushingrolls and the peripheral movements executed thereby in contact with theplant leaves, it may be helpful to review the physical characteristicsof the plant leaves .or vegetable units which are processed inaccordance with the present invention.

The plant leaves which are designed to be processed in accord with theinvention, and particularly those of the classes mentioned above,consist mainly of fibers and substances extraneous to such fibers, bothof which components possess widely differing physical characteristics.Extraneous substances consist mainly of a mass of sacks or cellscontaining plant elements in a more or less liquid state. The containingsacks are of a delicate membranous-like nature, rupturable by relativelyslight pressure. It has been determined that by rupturing all the sacksof extraneous substances, the contained elements may be liberated, andalso that those substances adhering to the fibers may be completelydetached therefrom in such manner that the fibers are separated in amore or less complete state from all extraneous substances by washing inwater.

Fibers contained in the plant leaves are of relatively denser structurethan the extraneous substances. A physical characteristic of thosefibers is one of relative elasticity. This property may be understoodfrom an examination of the structure of a fiber strand. A strand is abuilt up structure composed of ultimates or fibrils, held together bythe binding or gummy property of ligneous substances. Those ultimatesare cotton-like in appearance, are long in relation to their thickness,pointed at both ends, and enclose a cavity, presenting a cellularstructure, thickwalled in relation to the enclosed cavity. Thecushioning effect thus presented permits pressure to be applied to themof a degree greater than that required to rupture the aforesaid sacks,and upon release of pressure, the cellular ultimates recover theiroriginal dimensions. Ligneous substances binding the ultimates togetherare of a more or less viscid nature, and an appreciable time elapsesbefore pressure causes them to flow.

The combination of elasticity and cumulative cushioning property derivedfrom the many ultimates forming a strand of fiber, and the appreciabletime taken for viscous ligneous substances to begin to flow, permitspressure of a momentary nature to temporarily depress or flatten thefiber strands from which they recover their original dimensions uponrelease of said pressure, at the same time preserving the originaltensile strength of the fiber strands by avoiding flow or displacementof the binding ligneous substances.

The sacks of extraneous substances are generally smaller than thethicker and denser fiber strands, therefore those occupying positionsbetween the strands are protected from the pressure required to rupturethem. The object of depressing or flattening the strands is to exposethose sacks to pressure, thereby causing them to be ruptured and to bedetached from adhering to the fibers in so complete a manner that thefibers are separable from the extraneous substances by washing in water.

In order that no longitudinal stresses be imposed upon the fibers of theleaves in order to obtain such fibers in unbroken and undamaged form,specific apparatus is necessary, operating in a critical manner in orderto attain these results. Therefore, the invention contemplates theapplication of pressure to the plant leaves of such a nature as to causea temporary flattening of the fibers as well as the exposing of thesacks of extraneous substances to the rupturing and detaching action ofsuch pressure, these two results being executed simultaneously. Thissimultaneous differential action upon the fibers of the plant leaves andupon the extraneous plant matter surrounding them is preferablyexercised by rneans of a series of rotary cylindrical rollers,preferably of metal or other rigid surface, presenting a plurality ofsuccessive gaps between sets of superposed rollers, which gaps areconstant irrespective of the thinness of the material passing betweenthe rollers. The gaps between these rollers are adjusted for theparticular material being handled and generally corresponds to a spacewhich is less than the thickness of the sacks of the extraneoussubstances of the plant leaves being processed and approximately equalto the thinnest part of the thinnest fibers contained in the vegetableleaves. This arrangement permits the flattening of the fibers for thepurpose of presenting the sacks of extraneous substances to therupturing and detaching effects of the pressures exerted by the rolls.

It has been determined that a cooperative relationship exists betweenthe peripheral speed of the hard-surfaced rollers and the materialpassing through the gaps formed by the successive pairs of rollers.While such speeds may vary from 1,000 to 3,000 feet per minute, theoptimum speed in the handling of the leaves of the Sansevieria plant isapproximately 2,000 feet per minute. At such speeds the fibers which aredepressed or flattened temporarily regain their original dimensions uponthe release of pressure and the ligneous elements contained within thefibrous strands remain undisturbed in view of the insufficient time forsuch elements to begin to flow, whereupon the fiber strands retain theiroriginal tensile strength unimpaired. Speeds in excess of the optimumspeeds are desirable in order to increase the capacity of the apparatus.However, these speeds are limited by the capability of the operators tofeed the successive leaves into the first set of rollers for thepressing operation. Speeds materially lower than the optimum speed havethe disadvantage of prolonging the duration of the pressure between ther rollers which results in the displacement of the ligneous elements andtheir consequent flow, which is responsible for a reduction in thetensile strength of the fiber strands. Another disadvantage of slowerspeeds is the creation of stresses of a longitudinal nature in thefibers which produce a weakening and possible tearing thereof. Thisaction results from the tendency of the extraneous substances to flowbackwards as the vegetable leaves pass between the rollers. Thesesubstances, as they accumulate at the entry of the rollers, present aresistance against forward pull of the fibers which have already beengrasped between the rollers which gives rise to the undesired stressingof the fibers in a longitudinal direction.

The lowest permissible peripheral speed of 1,000 feet per minute may beemployed in the processing of plant leaves of greater succulence thanSansevieria, for example, some of the Agaves.

At the critical optimum speeds, the unpressed part of the vegetableleaves, as they begin to enter between the rollers, present an obstacleto the slower backward flow of the extraneous substances and byarresting this backward flow these extraneous substances are deflectedand caused to flow in lateral directions relative to the forward passageof the vegetable leaves. The lateral movement of the extraneous matterprevents a build-up of this matter at the rolls to preclude thepossibility of undesirable longitudinal stresses being imposed upon thefibers.

The material discharged from the roller crushing apparatus consists of amixture of fibers together with extraneous substances which have beenmore or less completely detached from the fibers, and are in a more orless fragmented condition. Separation of the fibers from thoseextraneous substances can be effectively carried out by a simpleoperation of washing in water, and may be carried out as a separateoperation.

The final separation of extraneous matter from the fibrous matter isetfected by washing the fibers with water and repeatedly entraining thefibers while permitting the extraneous matter to be washed therefrom. Inaddition to the washing effects by the current of water, the separationbetween the two components of the plant leaves is aided by thedifference in density between the fibers and extraneous matter, and theseparation is ultimately effected by a centrifuging operation whichaccelerates the separating effects.

Other objects and purposes will appear from the detailed description ofthe invention following hereinafter, taken in conjunction with theaccompanying drawings, wherein Fig. 1 is a front elevation of apreferred embodiment of our invention;

Fig. 2 is a plan view thereof;

Fig. 3 is a vertical sectional view along line 3-3 of Fig. 1;

Fig. 4 is an enlarged longitudinal section of the initial part of thewashing and separating apparatus;

Fig. 5 is a longitudinal sectional view of the final part of the washingand separating apparatus; and

Fig. 6 is a sectional view of the frame at the roll spacing adjustingmeans thereof, taken along line 6-6 of Fig. 2.

In the drawings the main frame of the machine F is shown anchored to afoundation B of any suitable design. A pair of longitudinally extendinghorizontal frame members 10 and 10 are laterally displaced on thefoundation B. Vertical pillars 11 and 12 are mounted at the forward endand at an intermediate point of frame member 10 and vertical pillars 11,12' are mounted at corresponding points of frame member 10. The verticalpillars 11 and 12 are superposed by a horizontal frame member 13, andanother frame member 13' of the same length as member 13, extendsbetween posts 11', 12' and beyond the latter in order to providemounting space for the driving elements of the washing and cleaning unitof the apparatus. The parts of the frame assembly described above aremaintained in integrated relation by means of bolts and nuts. Theconnections between the lower frame members 10, 10 and the verticalposts are designated by numerals 26, while the connections between theupper frame members 13, 13' and the vertical posts are designated bynumerals 27. Spacers 25, of natural or silicone rubber or of resinous orsolid fibrous material, are disposed between the upper frame members 13and 13' and the posts 11, 11 and 12, 12' in order to provide a variablebut unyielding displacement between the hard-surfaced cylindricalcrushing rolls 17a, 17b and 17c mounted upon and extending between theupper frame members 13, 13' and corresponding rolls of the same size,18a, 18b and 180, mounted upon and extending between the lower framemembers 10, 10'. Journal bearings 15 are mounted on the underside of theframe members 13 and 13 and corresponding journal bearings 16 aremounted upon the upper side of the frame members 10, 10, in order tomount the axles 21 of the upper rolls and the axles 20 of the lowerrolls in the respective upper and lower sets of frame members so thatthe gaps formed between the rolls bear a fixed predetermined relationwith respect to the plant leaves adapted to be passed therebetween. Thegap corresponds to the thinnest part of the fibers of the leaves and issmaller than the thickness of the extraneous matter surrounding thefibers, so

that as the material is passed between the rollers the thicker parts ofthe fibers will be compressed temporarily while theextraneous matterwill be pressed and broken and flow laterally of the fibers to eifect adetachment of the extraneous matter from the fibrous material.

At the front end of the machine a pair of frame members 14, 14' aremounted on the front end of the vertical posts 11, 11', respectively.Journal bearings 31 and 31 are mounted on the front end of the undersideof these frame members and are adapted to receive the journals of aroller 33 operating as a companion to roller 32, which is mounted injournal bearings 30, 30, fixedly attached to the rear edges of thevertical posts 11, 11', respectively.

An endless band 34 is entrained over rollers 33, 32 so that operatorsstanding on opposite sides of the endless band 34 may present the leavesof the plants to be decorticated to the action of the first set ofcrushing rolls 17a and 18a .with the points of the plant leaves foremostwith the plants in a series of overlapping layers disposed in parallel.

The crushing rolls are driven from any suitable prime mover such as anelectric motor, internal combustion engine or the like, by atransmission belt 40 driving a pulley 41 which may be coupled to thedrive shaft 20a of the first roll 18a either directly or through theintermediary of a clutch. The drive to the other rolls, operating at thesame speeds, may be transmitted in any suitable way. As shown in Fig. 3,the drive to the superposed upper roll 17a is transmitted by theintermeshing gears of the same size 42 and 43 mounted upon therespective roll shafts 20a and 21a. The drives to the next successiveupper rolls 17b and 17c are transmitted through the intermediary ofsprockets mounted on the front end of the shafts 21a and 21b andsprocket chain 44 extending between the aligned sprockets of the latter,and sprocket chain 45 extending between aligned sprockets on the shafts21b and 210. Likewise the transmission from the first lower roll 18a istransmitted to the other rolls by means of sprocket chain 46 extendingbetween aligned sprockets on the forward end of shafts 20a and 20b andsprocket chain 47 extending between aligned sprockets on the forward endof the shafts 20b and 200. A second sprocket 50 is mounted on theextreme end of shaft 20a, in alignment with a sprocket 51 mounted on theshaft of roller 32 in order to transmit the drive to roller 32 and theconveyor belt 34 entrained thereby by means of chain 48.

A second sprocket is also mounted near the right end of shaft 20c inalignment with a sprocket 54 on a shaft 55 mounted on the far end oflower frame members and 10' for the purpose of transmitting the drivethrough sprocket chain 56 to the movable parts of the washing and finalseparating units of the installation. This installation consists of aflighted conveyor 60 trained over lower and upper rollers 57, 58, andinclined to the vertical. This conveyor operates at the outlet end ofthe roll crushing apparatus wherefrom emanate the fiber in wisp formtogether with fragmented tissue or extraneous matter and juices in sprayform. The conveyor travels at a higher speed than the peripheral speedof the crushing rolls and serves to carry up on the conveyor flights 61successive batches of the components of the leaves in a separatedcondition for introduction into the washing and cleaning units of theinstallation, as shown in Figs. 1, 2, 4 and 5, which are mounted onframe supports F and F".

The fibers with some of the extraneous matter attached thereto arecarried into the field of operation of Water sprays 62, 62 acting indiverse directions under a spray shield 69 forming part of the washerhousing. These sprays are fed by conduits 63, 63 at the upper ends ofthe unit which are responsible for the initial washing away of theextraneous matter from the fibers and the removal thereof from thewasher casing.

The washer frame consists essentially of an inclined reticulated sluiceprovided with openings 71 of sufficient size to carry away the flowingwater with the particles of extraneous matter intermixed therewith. 'Theopenings 71 are so small that they do not cause any loss of the fiberswhich are travelling along the sluice. A sump 72 forms the base of thewashing unit for carrying off the wash water and particles of extraneousmatter to a suitable point of disposition through the outlet 73, whichmay be provided with a regulating valve. The effluent not only carriesaway the plant juices including chlorophyll but also the tissues whichare in highly frag:

mented state and of a much higher density than the fibers. The greaterdensity of the extraneous matter gives rise to a stratification betweenthis matter and the fibers so that the tendency for the removal of thelatter is enhanced as the material travels along the washing channelalong the openings 71.

In order to supplement the cleaning action afforded by the water sprays,the fibers are repeatedly arrested in their travel down the sluice bymeans of sets of pin members 75 and 75 mounted in cross-bars 95 and 96,respectively, extending across the width of the machine, along spacedparts therealong. Five sets of cross-bars 95, 96 are shown, but agreater or lesser number may be used, depending upon the length of thewashing channel and the degree of cleaning sought. Each set of crossbars95, 96 is mounted at the opposite ends of rocker arms 76, which arms arepivotally mounted on posts 77 disposed along opposite sides of the roofof the washing channel. Oscillating movements are imparted to the rockerarms 76 by means of rollers 78 which are mounted on a common bar 79 oneach side of the machine, and which execute a limited to-and-fromovement by virtue of a yoke or terminal strap 80 connected thereto andactuated by an eccentric 81 formed adjacent to each end of shaft 81,mounted on the end of the frame member F. The pins 75, 75 operate withinopenings in the cover 69 of the washing apparatus and are displacedsuccessively along the width of the washing apparatus in the successiverocking unit assemblies.

The rollers 78 alternately act upon the high points of the rocking bars76 to alternately depress sets of pins 75 and 75' to give them a rapidup and down movement, separated by a pause in time caused by the dwellin the rocker arms 76. The pins 75', which are shown as extended withinthe sluice, cause an entrapment of the fibers in their downward travelwhile the water flow serves to wash away the extraneous particlestherefrom. The raising of the pins 75, occasioned by a rocking of thebar 76, results in a release of the fibers for travel down the floor 70of the sluice until they are again entrapped by a lower row of pins 75which are now rapidly lowered into the field of flow of the water withthe fibers suspended therein. This intermittent entrapment and releaseof the fibers results in their effective entanglement in tow form whilereleasing most of the extraneous matter therefrom. The rapidity of themovement of the pins 75, 75' causes them to come into position in thechannel before the fibers which have been released from a higher groupof pins pass the points where they may be engaged by the succeeding setof pins. The pause in the movement of the pins provides for theretention of the fibers while they are subjected to the washing actionof the water current in the channel.

The separating action is carried out in its final stages by thepresentation of the fibers and water with whatever portion of theextraneous matter is retained thereby to the field of operation of arotary drum 85 provided with vanes 86 projecting from the peripherythereof, which drum rotates in a counterclockwise direction within ashell 86' which is perforated at the left side thereof with openings 87.These openings may be /s" in diameter with a scattered pitch of aboutThe water and extraneous particles are thrown out centrifugally throughthe openings 87 for reception by a suitable sump while the fibers areentrained by means of the vanes 86 and are delivered to the channel 88in wisp form for delivery to a suitable conveyor or repository for finaldrying. The resultant product is the fibrous content of the plant leavesin tow form and having but insignificant amounts of extraneous matteradhering thereto which fly or break away from the fibers in the courseof the subsequent spinning and yarn manipulating operations.

A regulating valve 89 may be provided at the outlet end of the washingchannel to regulate the flow of the water therethrough. This bafiieelement may be used to control the degree of flotation of the fibrousmaterial above the layer of the particles of extraneous matter as thesame flow down the channel while being subjected to the arrestingmovements of the pins 75, 75'.

The drive for the movable units of the cleaning apparatus may be takenfrom the drive of the roll crushing unit. Thus the conveyor 60 may bedriven from transmission shaft 55 at the rear lower end of the frame bymeans of sprocket chain 64 extending between a sprocket on this shaftand another smaller sprocket mounted on shaft 65. A second sprocket ismounted on shaft 55 for transmitting rotary movement to shaft 81 bymeans of sprocket chain 66. Shaft 81 carries the eccentrics 81 forimparting reciprocating movements to the rocking rollers 78 foractuating the fiber entraining pins 75, 75.

The rotary drum 85 is driven by means of a reverse belt 98 trained overa pair of pulleys mounted on the ends of shaft 55 and the rotary shaft99 supporting the rotary drum 85.

Variations in the drive for the several moving elements of the apparatusmay be made in dependence upon the needs of individual installations.

It is contemplated that guard housings be used wherever such may benecessary, as well as additional SUIIIPS for conducting away the liquidcomponents of the material operated upon by the machine. For example, asump may be provided on the outside of reticulated screen 86 which may,if desired, be combined with sump 72. Likewise a screen or sump may beprovided at the bottom of the conveyor 60 for the purpose of carryingaway the plant juices which issue from the last of the crushing rollersand which are not entrained by the solid matter carried on the conveyor60 to the washing unit.

The amount of wash water employed in the washing of the fibers may becontrolled by the introduction of water through the water inlet pipes63" at each side of the head 7 of the washing channel (Fig. 4)' tosupplement the quantity of spraying water fed through conduits 63, 63'.

The installation as described represents a preferred embodiment of theinvention for obtaining the fibers from plant leaves, for example, theleaves of the Sansevieria ;f,

plant, the processing of which has heretofore proven uneconomical.

While I have described my invention as embodied in a specific form andas operating in a specific manner for purpose of illustration, it shouldbe understood that I do not limit my invention thereto, since variousmodifications will suggest themselves to those skilled in the artwithout departing from the spirit of my invention, the scope of which isset forth in the annexed claims.

I claim:

1. An apparatus for decorticating of plants leaves to obtain the fiberstherefrom directly and exclusively in a condition of tow, whichcomprises a machine frame having lower and upper frame parts supportingrotary members for crushing the plant leaves only, said rotary memberscomprising a plurality of hard-surfaced cylindrical rolls mounted atdisplaced points along the lower part of said frame, a plurality ofcompanion hard-surfaced rolls identical to said first-mentioned rollsmounted on the upper part of said frame in overlying relation to saidlastmentioned rolls, spacers between the upper and the lower parts ofsaid frame to fix the extent of the gap between said rolls to correspondto the thinnest dimension of the fibers in the plant leaves and lessthan the thickness of the extraneous substances surrounding said fibers,and means for rotating all of said rolls at a'substantially uniformperipheral velocity which crushes the plant leaves with no transversestrains or breakages and which induces no harmful obstruction to thetravel of the fibers through the gaps of said rolls to cause theirtensile stressing with a consequent tearing and damage thereof.

2. An apparatus as set forth in claim 1 wherein said rolls have adiameter of approximately eighteen inches and a peripheral velocity of1,000 to 3,000 feet per minute.

3. An apparatus as set forth in claim 1 wherein said spacers are formedof thin sheets of rubber to impart a slight degree of springiness to theroll mountings.

4. An apparatus as set forth in claim 1 wherein is provided three setsof heavy rolls to effect a crushing of the plant cells containing theextraneous substances.

References Cited in the file of this patent UNITED STATES PATENTS738,668 Ellis Sept. 3, 1903 1,021,269 Schlichten Mar. 26, 1912 1,089,261Pos Mar. 3, 1914 1,601,977 McHenry Oct. 5, 1926 1,983,454 Haynes Dec.4-, 1934 2,238,225 Lang Apr. 15, 1941 2,355,999 Patterson Aug. 15, 19442,408,749 Berg Oct. 8, 1946 2,567,938 Hoffman Sept. 18, 1951 2,571,108Burkardt Oct. 16, 1951

